Stress and physical health

Introduction: Researchers measured the body's defenses against infection, and illness, in students during a calm period and during final exams.

Participants: 64 second-year medical students (33 women and 31 men) at a university in Ohio volunteered and gave informed consent. Race/ethnicity was not reported.

Method: Each student gave a blood sample and completed a stress questionnaire one month before final exams and again during finals week. Researchers measured the activity of natural killer cells, a type of white blood cell that fights viruses. Students also reported any cold or flu symptoms during the two weeks after each blood sample.

Results and Discussion: Natural killer cell activity was 18% lower during finals week than one month earlier. In the two weeks after finals week, 31% of students reported cold or flu symptoms, compared with 11% in the two weeks after the earlier sample. Students who reported the most stress showed the largest drops in natural killer cell activity.

Introduction: Researchers studied whether long-term stress slows the healing of wounds.

Participants: 26 adults aged 50 to 80 who had cared for a family member with dementia for at least two years, and 26 adults who were not caregivers, matched to them in age, gender and income. In each group, 19 of the 26 participants were women.

Method: With informed consent, each participant received a small, standard 3.5-millimeter skin wound on the forearm, made by a physician under local anesthetic, like those used in routine medical tests. Researchers photographed the wound every day and recorded the number of days until it was fully healed. Participants also completed a questionnaire about how stressed they felt.

Results and Discussion: The caregivers' wounds took an average of 46 days to heal, compared with 37 days for the noncaregivers, about 24% longer; the difference was statistically significant. The caregivers also reported feeling more stressed.

Introduction: Researchers tested whether learning to manage stress could lower blood pressure in adults with stressful jobs.

Participants: 120 adults aged 30 to 60 who worked full-time in high-pressure jobs and whose blood pressure was above the healthy range, but who were not taking blood pressure medication. Of the participants, 55% were women; they reported their race/ethnicity as 40% White, 30% Black, 20% Hispanic or Latino and 10% Asian.

Method: Participants were randomly assigned to an 8-week program or to a waitlist group that received the program after the study. The program met weekly for 90 minutes. It taught slow breathing, muscle relaxation and meditation for calming emotional reactions to work stress, and it gave practice in listing work problems and planning steps to solve them. A nurse who did not know which group each participant was in measured blood pressure before and after the 8 weeks.

Results and Discussion: The program group's average systolic blood pressure (the top number) fell from 142 to 133, a drop of 9 points, while the waitlist group's fell from 141 to 139, a drop of 2 points. The difference was statistically significant. Program participants also reported feeling less stressed at work.